From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
Balbir Singh <bsingharora@gmail.com>,
David Rientjes <rientjes@google.com>,
Hugh Dickins <hughd@google.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 5/7] mm: page_cgroup: check page_cgroup arrays in lookup_page_cgroup() only when necessary
Date: Wed, 30 Nov 2011 08:42:11 +0900 [thread overview]
Message-ID: <20111130084211.15fdefbf.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <1322563925-1667-6-git-send-email-hannes@cmpxchg.org>
On Tue, 29 Nov 2011 11:52:03 +0100
Johannes Weiner <hannes@cmpxchg.org> wrote:
> lookup_page_cgroup() is usually used only against pages that are used
> in userspace.
>
> The exception is the CONFIG_DEBUG_VM-only memcg check from the page
> allocator: it can run on pages without page_cgroup descriptors
> allocated when the pages are fed into the page allocator for the first
> time during boot or memory hotplug.
>
> Include the array check only when CONFIG_DEBUG_VM is set and save the
> unnecessary check in production kernels.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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next prev parent reply other threads:[~2011-11-29 23:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-29 10:51 [patch 0/7] mm: memcg fixlets for 3.3 v2 Johannes Weiner
2011-11-29 10:51 ` [patch 1/7] mm: oom_kill: remove memcg argument from oom_kill_task() Johannes Weiner
2011-11-29 10:52 ` [patch 2/7] mm: unify remaining mem_cont, mem, etc. variable names to memcg Johannes Weiner
2011-11-29 10:52 ` [patch 3/7] mm: memcg: clean up fault accounting Johannes Weiner
2011-11-29 10:52 ` [patch 4/7] mm: memcg: lookup_page_cgroup (almost) never returns NULL Johannes Weiner
2011-11-29 10:52 ` [patch 5/7] mm: page_cgroup: check page_cgroup arrays in lookup_page_cgroup() only when necessary Johannes Weiner
2011-11-29 11:00 ` Michal Hocko
2011-11-29 23:42 ` KAMEZAWA Hiroyuki [this message]
2011-11-29 10:52 ` [patch 6/7] mm: memcg: remove unneeded checks from newpage_charge() Johannes Weiner
2011-11-29 10:52 ` [patch 7/7] mm: memcg: remove unneeded checks from uncharge_page() Johannes Weiner
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